I went through the blog at
http://blog.mikemccandless.com/2010/06/lucene-and-fadvisemadvise.html for a
detailed description on segment merge effects on IO Cache. As the comment
section clarifies, SEQUENTIAL advise has been implemented correctly from
kernel 2.6.29 upwards.
But we don't have the SEQUENTIAL impl, only the O_DIRECT impl. Can newer
kernel versions use SEQUENTIAL for lucene segment merges? Are there other
factors in play here, that lucene is not implementing it.
--
Ravi